Heavy metal pollution of agricultural soil has become a major serious concern. The development of suitable control and remediation strategies for heavy metal contaminated soil has become critical. The outdoor pot experiment was conducted to investigate the effect of biochar, zeolite, and mycorrhiza on the bioavailability reduction of heavy metals and its subsequent effects on soil properties and bioaccumulation in plants as well as the growth of cowpea grown in highly polluted soil. Zeolite, biochar, mycorrhiza, zeolite with mycorrhiza, biochar with mycorrhiza, and soil without any modifications were the six treatments used. The experiment was conducted with a completely randomized design and four replications. The results indicated that the combination of biochar with mycorrhiza had the highest values of root and shoot dry weight and the lowest heavy metal concentrations in root and shoot as well as bioconcentration and translocation factors for all heavy metals. The highest significant reductions in the availability of heavy metals over the control were found with biochar with mycorrhiza, which were 59.1%, 44.3%, 38.0%, 69.7%, 77.8%, 77.2% and 73.6% for Cd, Co, Cr, Cu, Ni, Pb and Zn, respectively. The application of biochar and zeolite either alone or in combination with mycorrhiza increased significantly soil pH and EC compared to mycorrhiza treatment and untreated soil. It can be concluded that the combination of biochar and mycorrhizal inoculation has great potential as a cost-effective and environmentally technique for enhancing heavy metal immobilization, lowering heavy metal availability and plant uptake, and improving cowpea plant growth.

The present study investigated the effect of foliar application of chitosan at 150 ppm and glycine betaine at 700 ppm on lettuce plants cv. Balady grown under well-watered and water deficit conditions in terms of growth, yield, quality, and water usage efficiency. The study was conducted in Qalubia Governorate, Egypt, during the two seasons of 2020/2021 and 2021/2022 on clay soil. Results indicated that water-stressed plants had a reduction in plant fresh weight, plant height, leaf area, and total yield, chlorophyll content and relative water content, while they exhibited an increase in total soluble solids, nitrate, and proline contents as well as water-use efficiency in both seasons. The foliar application of chitosan or glycine betaine to lettuce significantly improved plant performance under limited and normal irrigation conditions in comparison with untreated plants. The maximum positive effect was for chitosan foliar application. Overall, the results of this study indicated that foliar application of chitosan or glycine betaine was a substitute technology for improving the lettuce yield and quality as well as increasing water use efficiency under both irrigation regimes, but may be more efficient in lettuce plants subjected to a water deficit.

The harmful effects of pesticide misuse on human health and the environment have become evident; so, this study aimed to monitor pesticide residues in soils of vegetable fields collected from the Eastern Nile Delta region, Egypt and to assess the potential health risks associated with them. Pesticide residues were determined using gas chromatography-mass spectrometry. Obtained results revealed that 100% of collected samples were contaminated with pesticides; residues of 33 compounds were detected in analyzed samples belonging to different chemical groups. Most detected pesticides (44%) were non-persistent and 40% were moderately persistent. While 1313% and 3% were persistent and very persistent compounds, respectively. Also, 36.7% and 30% of samples have two and three pesticides. Chlorpyrifos and propamocarb were the most dominant compounds that had widespread use across the study area. The number of detected pesticides per crop ranged from 1 to 16 (potato soil), followed by cucumber and tomato (13 pesticides), while one compound was detected in sweet potato soil. Soil organic matter content had a positive correlation with the total concentration of pesticide residues; however, no correlations were found with soil clay, pH and electrical conductivity contents. The human health risks of pesticides in the study soils were within acceptable levels. However, more attention should be paid in the future to decreasing the pesticide load and take place pesticide residue monitoring on vegetable soils.